The animals don’t care about radiation. They will die of something else long before they die of radiation, some might even mutate in beneficial ways.

That seems like a rather uneducated guess. Some species of shark for example live a very long time (bordering on immortal), and orcas live as long as many humans.

So you’re saying animals care.

What animals think is unknowable. It’s just as valid to say they care as to say they don’t care. We can say that they do try to stay alive as long as possible. But what does it matter what their thoughts are anyway? Physics cares about radiation, biology cares. There is no way arbitrary human-introduced tissue damage from radiation is going to be good for any creature on earth. This is wrong, no buts about it.